Preparation of solids from carboxyl copolymers without solvent liberation



United States Patent 3,247,287 PREPARATHQN OFSOLEDS FROM CARBOXYL C0-POLYMERS WITHQUT SULVENT LIBERA'HGN John E. Masters and Darrell D.Hicks, Louisville, Ky., assignors, by mesne assignments, to CelaneseCoatings Company, a corporation of Delaware No Drawing. Filed Nov. 9,1962, Ser. No. 236,710

9 Claims. (Cl. 260-837) This application is a continuation-impart of ourcopending US. patent application Serial No. 788,046, filed January 21,1959, now abandoned.

This invention pertains t the polymerization of unsaturated acids andrelated compounds, with vinyl, vinylene or vinylidene compounds to formcarboxy cop-olymers. It is particularly related to processes for the-formation of solutions of carboxy copolymers which are capable of beingreadily cross-linked, and to methods for preparing molded articles orcastings from such polymer solutions.

Carboxy copolymers of unsaturated acids or their alcohol esters anddifferent unsaturated monomers are well known. They are prepared bypolymerizing with said difierent monomer an unsaturated carboxylic acidsuch as acrylic, crotonic, methacrylic, itaconic, maleic, the partialesters or partial salts thereof and .anhydrides of the polycarboxylicacids by solution or emulsion polymerization techniques well known tothose skilled in the art, the amount of carboxy component in thecomposition being from 1 to 80 weight percent based on the polymer.

In emulsion polymerization the drying of the coagulum is diflicultbecause of the great tendency of the polymer to coalesce. Subsequentmastication with cross-linking agents is difiicult. Accordingly,emulsion polymerized carboxy copolymers are generally used asfilm-forming materials rather than in pottings, castings, and the like.

Solution polymerization of acid monomers with other unsaturated monomersto form carboxy copolymers does not lend itself to formation oi moldedarticles because of the difiiculty of removing the solvent. Even when alow boiling solvent such as acetone is used, it is difiicult to formcastings free of entrained solvent or of bubbles resulting from solventliberation. While this invention is not limited thereto, the presence ofsolvents has prohibited an extensive use of carboxyl containingcopolymers in the potting and casting fields.

tile solvent in which the polymer is soluble and which reacts with thepolymer and/ or a cross-linking agent for the polymer under curingconditions, that is, at curing temperatures and, if necessary, in thepresence of a catalyst. It is understood, however, that underpolymerizing conditions, the solvent and the monomers are substantiallynon-reactive with each other. In other words, the polymerization mediumis a solvent which does not react with the monomer or the polymer duringpolymerization,

but which reacts with either the polymer or the crosslinki-ng agent orboth when the temperature is raised above the polymerization temperatureand a catalyst is used.

Polymer solutions are thus formed which can be mixed with cross-linkingagents to form cured materials without the need for solvent liberation.This not only renders the polymer solutions particularly suitable forpottings,

castings and encapsulations, but also provides a convenient reactionmedium for making high polymers which otherwise would be of little valuein pottings, castings,

encapsulations etc. because of their extreme viscosities.

Reactive solvents which are employed in accordance with the practice ofthis invention are saturated carboxylic acids or an-hydrides of suchacids, alcohols and epoxides, each boiling at 150 C. or above, and eachbeing liquid at the polymerization temperature employed, that is, theyhave melting points below the polymerization temperature used, generally60 C. to 150 C. The viscosity of the solvents should not be greater thancentipoises at the polymerization temperature.

Of acids, alcohols and epoxides serving as reactive solvents herein,rnonocarboxylic acids, monohydric alcohols, and monoepoxides aresuitable but polycarboxylic acids, polyhydric alcohols, and polyepoxidesare preferred. Suitable saturated monocarboxylic acids, includinganhydrides, are benzoic acid, propionic acid or anhydride, butyric acidor anhydride, capric acid, caproic acid, myristic acid, and palmiticacid.

Among the preferred polycarboxylic compounds are dicarboxylic acids andanhydrides and particularly mixtures of such anhydrides or acids whichform liquideutectics. Examples of polycarboxylic acids or theiranhydrides are phthalic anhydride, succinic anhydride, glutaric acid,sebacic acid, isosuccinic acid, and mixtures of acids such astetrahydrophthalic and hexachloroendomethylenetietrahydrophthalic acidsand hexahydrophthalic anhyride.

Monohydric alcohols which are most advantageously used in accordancewith the invention are those which are not readily liberated by heatingafter the polymer is made. Such alcohols are aliphatic alcohols havingboiling points above C. and usually over six carbon atoms. Included arecapryl alcohol, stearyl alcohol, lauryl alcohol, Z-ethyl-hexyl alcohol,nonyl alcohol, cyclohexanol, b-enzyl alcohol, l-butoxy-Z-ethanol,l-butoxyethoxy-Z-propanol, l-methoxyethoxy-Z-ethanol and the like. It isunderstood that the alcohols as used herein include both the monohydricalcohols and the monohydric ether alcohols. Thus, the commerciallyavailable Cellosolves and Carbitols boiling above 150 Cfare used herein.These compositions are the reaction products of monohydric alcohols withethylene and propylene oxides such as I-hexoxy-Z-ethanol, and ethoxyethanol. While saturated acids and alcohols are usually employed, it isnoted that unsaturated alcohols and acids are usable depending on thereactivity of the double bond under polym-- erization conditions. Thus,fatty acids of the drying oil type such as soya and linseed oil andstearic acids as well as long chain alcohols can be used.

Of the alcohols, saturated polyhydric alcohols are preferred which boilabove 150 C. and which in admixture with the monomers form, at thereaction temperature, liquid solutions having viscosities not exceeding130 centipoises. Particularly suitable are the high molecular weightglycols. However, glycerin, sorbitol, trimethylol propane and the likecan also be used. Suitable glycols are, for instance, ethylene glycol,propylene glycol, diethylene glycol, 1,5-pentanediol, tripropyleneglycol, di propylene glycol, tetraethylene glycol, triethylene glycol,xylylene glycol, dihydroxyethyl ethers of bisphenol, etc. It isunderstood that the term glycols as used herein also includes both thedihydric alcohols and the dihydric ether alcohols. Thus, thecommercially available .Carbowaxes are contemplated. These are mixturesof polyoxyethylene glycols. Those mixtures having average molecularweights of from 200 to 1000 are particularly desirable. templated.

The third class of reactive solvents is saturated mono- Thepolyoxypropylene glycols are also con- 3 and poly-epoxides, especiallymonoand poly-glycidyl ethers and esters of alcohols and acids. Examplesof mono-epoxide solvents are such monoepoxides as styrene oxide,glycidol, phenyl glycidyl ether, glycidyl acetate,

glycidyl benzoate, butyl glycidyl ether, and the like.

Among the polyepoxides which can be used as reactive solvents areglycidyl polyethers of polyhydric alcohols Other epoxides are alsoincluded, for example, epoxidized drying oils, acids and esters. It isnoted that the reactive solvent need not be a liquid at roomtemperature. It is necessary only that it have a viscosity of not morethan 130 centipoises at the polymerization temperature. It is a lowmelting compound which will be liquid at the polymerization temperature.The reactive solvents set forth hereinbefore make excellent reactionmedia. -In some cases upon cooling, crystalline slids result which canbe readily liquified on heating.- If desired, the solid polymerdiluentcompositions can be pulverized for convenience in use.

Methods of polymerizing the alpha-beta unsaturated acids with variouscomonomers are ,well known. Polymerization is effected by conventionalsolution polymerization techniques, except that the polymerizationmedium contemplated herein is used as a solvent rather than one of theconventional volatile media. The amount of polymerization mediumemployed will depend upon several things; the viscosity of the medium,the molecular weight of the polymer made, and the solubility of thepolymer in the medium. Thus, when a low molecular weight monocarboxylicacid, monohydricalcohol, or monoepoxide is employed, less will berequired when a more viscous composition, such asa diepoxide or a highermolecular weight alcohol, is used. In addition, if a low molecularweight polymer is made, not as much medium is required as when a highermolecular weight polymer is prepared. This being the case, it can bestbe stated that sufiicient polymerization medium is used to form, at thereaction temperature, a solution of the resulting carboxy copolymer inthe polymerization medium. Generally, the amount of polymerizationmedium will be 30 to 40 percent with 70 to 60 percent by weight carboxycopolymer. From 5 to 80 parts acid, preferably to 50, are reacted with95 to parts comonomer, the polymerization reac tion being carried out attemperatures of from 60 C. to the reflux temperature, generally 60 C. to150 C., if de sired, at a pressure slightly above atmospheric. Thepolymerization reaction is, of course, accelerated by the use of heatand other conditions such a peroxide cataylst, e.g. benzoyl peroxide,cumene hydroperoxide, tertiarybutylor mixtures thereof. Preferred acidsare alpha-beta hydroperoxide, phthalic peroxide, acetyl peroxide,lauroyl ethylenically monounsaturated monocarboxylic acids of not morethan four carbon atoms. Desirable partial esters are half esters offumaric acid, maleic acid or maleic anhydride, the alcohols having notmore than 20 carbon atoms, for example, 'monobutyl maleate, monooctylfumarate and monocetyl maleate. Preferred acid esters are those for-medwith alcohols having from lto 10 carbon atoms.

Polymerized with the alpha-beta unsaturated acid is a monoethylenicallyunsaturated monomer. By a monoethylenically unsaturated monomer isintended an organic compound containing a single CH=CH group, or moreespecially a CH =C group. Included are vinyl, vinylene, and vinylidenemonomerscopolymerizable with the alpha-beta unsaturated acid.Particularly important are vinylidene and vinyl aromatic compounds, forin-' stance, styrene, vinyl toluene, alpha-methyl styrene, thehalo-styrenes, etc. having a single vinyl group and free of othersubstituents capable of reacting with an unsaturated acid, in otherwords, a monounsaturated vinyl aromatic compound. Other suitablemonomers are isopropenyl toluene, the various dialkyl styrenes, ortho-,meta-, and para-chloro styrenes, bromo styrenes, fluoro styrenes, cyanostyrenes, vinyl naphthalene, the various alpha-substituted styrenes,e.g., alpha-methyl styrenes, alpha-methyl para-methyl styrenes, as wellas various di-, tri-, and tetrachloro, bromo, and fluoro styrenes. Alsovaluable are acrylic, methacrylic, and crotonic esters of saturatedalcohols, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl,(sec)butyl, amyl, hexyl, heptyl, octyl, decyl,

I dodecyl, etc. esters of acrylic, methacrylic and crotonic acids,generally alpha-beta unsaturated monocarboxylic acid esters of saturatedmonohydric alcohols, the acids having not more than four carbon atomsand the alcohols having not more than twenty carbon atoms.

As indicated hereinbefore, the preparation of carboxylcontainingcopolymers is known. Accordingly, it is unnecessary to set forth allmonomers known in the art. For example, other monomers so used are vinylaliphatic cyanides of not more than four carbon atoms, such as tures ofthe monomers can be copolymerized with the alpha-beta unsaturated acidsto form the carboxyl-containing copolymer. A desirable mixture is acombination of an acrylic or methacrylic ester with styrene or vinyltoluene. Of course, when mixtures are employed a certain degree ofselectivity must be exercised. Thus, it is preferred not to use vinylacetate or similar esters with styrene and the like. Likewise, therewill be certain preferred combinations of monomers and unsaturated acidsforming the copolymers. For instance, it is undesirable to use vinylaromatics, e.g., styrene, with maleic or fumaric or their half esters,because of the tendency of such half esters to polymerize in constantproportions with other monomers. In addition, it is desirable not to usemalei'c acid with a vinyl acetate monomer.

It is understood that while many monomers can be used in the preparationof the copolymer and that while a wide variety of reactive solvents canbe used, all these combinations cannot necessarily be used withequivalent results. There are necessarily certain preferences and somecombinations of monomers and solvents which will give better resultsthan certain other combinations. 'Thus where the polymer is a copolymerof styrene or vinyl toluene and acrylic or methacrylic acid,h6X3JhYdIOPhthfllie acid anhydride is a preferred reactive solventrather than phthalic an'hydride which is not as suitable. On the otherhand if a hydroxy compound such as a monohydric alcohol or a glycolisused as the reactive solvent,'acrylonitrile desirably should not be usedas a monomer in preparation of the carboxy copolymer. In the case ofvinyl aromatic monomers, it has been found also that vinyl toluene ismore compatible in the systems contemplated herein than styrene. Inaddition if the carboxy copolymer is made from cro-tonic acid and vinylacetate, it is preferred to start the polymerization without thereactive solvent and to add the solvent during a later stage ofpolymerization. With respect to the reactive solvent, it has also beenfound that decreasing the amount of reactive solvent leads to theformation of longer chain polymers having higher tensile strengths.

In forming cross-linked compositions from the carboxycopolymer solutionsof this invention, if the diluent is a polyepoxide, the com-position canbe cnoss-linked by heat alone or with the addition of a small amount ofcatalyst, otherwise any of the known polyfunctional cross-linkingcompositions which react with the copolymer or the reactive solvent asthe case may be, such as anhydrides, alcohols, cpoxides, isocyanates andthe like, can be used depending, of course, on the solvent system.However, in our preferred embodiment, cross-linking agents are used suchthat an epoxy-'carboxy system, or preferably a car boxy-epoxy-acidanhydride system results. Thus, if a carboxylic acid anhydride is usedas the reactive solvent, a polyepoxide such as a glycidyl polyether of adihydric phenol is preferred as the cross-linking agent. It the reactivesolvent is an epoxide, a dibasic acid anhydride or polybasic acidanhydride is used as the cross-linking agent. In the case of glycols,monoepoxides or monocarboxylic acids as reactive solvents, a polyepoxideand an anhydride are preferably both used to form the cross-linkingsystem. If the copolymer has a high carboxyl content, the use of ananhydride is not essential. But in many cases, it will be desirable.

In making moldings, castings and the like by the teachings of thisinvention, the carboxy copolymer and the reactive solvent can be furtherreacted with each other, as where a polyepoxide is employed as thereactive solvent, or with a third compound such as polyisocyanate, zincoxide, a caustic alkali, a primary or secondary amine or a polyamine Insuch a system, the carboxy-containing copolymer and the polyepoxide arepreferably used in a ratio of one carboxyl equivalent of copolymer toone to two epoxide equivalents of polyepoxide and 0.01 to percent of acatalyst such as an amine or potassium hydroxide, BP etc., based on thetotal composition. The 00- polymer will have been made using oneequivalent epoxide solvent for each carboxyl equivalent ethylenicallyunsaturated acid. However, it is desirable to have acarboxy-epoxy-polycanboxylic acid anhyd-ride system, and preferably acarboxy-epoxy-alcohol-polycarboxylic acid anhydride system. Thus if thecarboxy copolymer is made in the presence of an acid anhydride, it ispreferred to employ a polyepoxide in the formation of the solid objects.In many instances, it will he even more desirable to use a polyepoxideand a polyhydric alcohol. carboxy copolymer is made with a polyepoxideas the reactive solvent, a polycarboxylic acid anhydride makes adesirable cross-linking agent. A combination of the acid anhydride and apolyhydric alcohol also makes a desirable cross-linking system.

In the formation of a carboxy-epoxypolycarboxylic acid anhydride system,the reactants are employed in ratios resulting in a cross-linkedthermoset composition, usually from 1 to 2 equivalents anhydride to 2equivalents polyepoxide to 0.2 to 0.8 equivalent copolymer. And eitherthe anhydride or the polyepoxide as the case may be, can be used as thereactive solvent with the other being subsequently added as across-linking agent. Moreover, all of the required anhydride orpolyepoxide need not be used as If the reactive solvent as anyadditionally-required can be added with the cross-linking agent.However, as a rule, all of the required anhydride or epoxide is used asthe reactive solvent. It is understood that the carboxy equivalent ofthe copolymer depends upon the amount of acid used in its preparation,and the ratios of polycarboxylic acid anhydride and polyepoxide dependupon this carboxy equivalency of the copolymer as set forth in theaforementioned ratio.

Since a preferred system is a carboxy copolymer-polycarboxylic acidanhydride-polyepoxide-poly hydric alcohol system, if the copolymerbecomes too viscous when either the an-hydride, or the polyepoxide aloneis used, the composition can be further thinned with an alcohol or thecopolymer can be made in the presence of an anhydride or epoxide-alcoholmixture. It is preferred to start the copolymer reaction in the alcoholmedium and then add anhydride or epox-ide if necessary to control theviscosity. In such a system, 1 equivalent polyepoxide is employed foreach carboxy equivalent copolymer and the anhyd-ride, polyepoxide, andpolyhydric alcohol are employed in amounts of 2 equivalents anhydride to2 equivalents epoxide to 0.4 to 1.6 equivalent alcohol. The total ratiowhen a polyhydric alcohol is used is, therefore, 1 equivalent carboxycopolymer to 3 polyepoxide equivalents, to 2 anhydride equivalents to0.4 to 1.6 equivalent polyhydric alcohol.

If a polycarboxylic acid is employed as the solvent, and a polyepoxideas the cross-linking agent, the ratio will be 2 equivalents polyepoxideto l carboxyl equivalent copolymer to 1 carboxyl equivalent acid. In ananhydride, copolymer, epoxide, carboxylic acid system, the ratio ofreactants is 1 equivalent copolymer to 3 equivalents epoxide, to 2-31equivalents anhyd-ride, to y equivalents car- 'boxylic acid where 3 :01to 0.8. Since the epoxide equivalent includes both monoepoxides andpolyepoxides, it should be pointed out that polyepoxide must be used ifa cross-linked final composition is to be obtained. A monoepoxide can beemployed as the reactive solvent and polyepoxide used later as at leastpart of the cross-linking agent. At least fifteen percent of the totalepoxide should be polyepoxide.

By an epoxide, anhydride, hydroXy-l or carboxyl equivalent is meant thegram equivalent weight based on the particular group, in other words,the weight in grams per epoxide, an'hydride, hydroxyl or carboxyl group.

It is understood that in the carboxy-epoxy curing system, a catalyst canbe employed if desired. Generally speaking, any of the known catalystswhich are activators for epoxy-carboxy reactions can be used to increasethe rate of cross-linking, for example, inorganic and organic bases,e.g. amines, quaternary ammonium hydroxides and alkali metal or alkalineearth metal hydroxides, examples are sodium hydroxide, calciumhydroxide, dimethylamino phenol, benzyl dimethylamine and the like.Particularly desirable catalysts are quaternary ammonium salts such asbenzyl trimethylammonium acetate and benzyl trimethylammonium chloride,etc. These activators are employed in catalytic quantities, say from0.01 percent to 5 percent based on the total compositions. Curingconditions will, of course, vary with the particular application. Ingeneral, the carboxy-epoxy composition with or without the anhydride andalcohol is heated at C. to 200 0, generally 180 C. to form across-linked infusible resin if no catalyst is used. If a catalyst isemployed, the copolymer-solvent composition is cured at a temperature offrom 125 C. to 200 C., the period depending upon the size of thecasting, varying from one to four hours with a catalyst and three totwelve hours when no catalyst is used.

In order more fully to illustrate the invention, the following examplesare included. The examples are for the purpose of illustration only, andit is intended that method described hereinbefore. The following tablegives the ratio of epichlorhydrin to polyhydric compound used to preparethe resins. The polyhydric compound reacted with the epichlorhydrin andthe epoxide equiva- The epoxides will be identified in the examples bytheir epoxide equivalent. Thus, when the epoxide used in the examples isa glycidyl polyether having a weight per epoxide of 190 obtained fromthe reaction of 10 mols of epichlorhydrin to one mol of bisphenol, thisepoxide is referred to as Epoxide 190 in the examples and table.Likewise, the epoxide obtained from the reaction of 2 mols ofepichlorhydrin to one mol of polyethylene glycol (molecular weight 200)is referred to as Epoxide 200.

In a one liter, three-necked, round-bottomed flask fitted with anagitator, thermometer, condenser and dropping funnel, the Epoxide 190and polyethylene glycol are heated to 125 C. In an Erlenmeyer flask, thevinyl toluene, methyl acrylate, methacrylic acid and catalyst are heatedwith agitation until complete solution results. This monomer-catalystsolution is then introduced into the flask containing the preheatedepoxide-glycol diluent by means of the dropping funnel. During theaddition of this monomer-catalyst solution, a period of one and one-halfhours, the temperature of the flask contents, are held below 125 C.After the addition is complete, the flask contents are held at 125 C.until reflux ceases, whereupon the flask is fitted for vacuumdistillation and any excess monomer is distilled off at mm. Hg and 117C. The resulting product is a percent solution of a /20/20 vinyltoluene/methyl acrylate/methacrylic acid polymer in a 50/50 mixture, byweight, of Epoxide 190 and a polyethylene glycol having a molecularweight of 300. The copolymer portion of the composition has atheoretical carboxyl equivalent of 430 while the total copolymersolution has a theoretical carboxyl equivalent of 860, epoxideequivalent of 760 and hydroxyl equiva lent of 600.

' B. Cured composition In a suitable container, 94.4 grams of thecopolymer solution of this example (0.108 carboxyl'equivalent ofcopolymer, 0.124 epoxide equivalent of Epoxide 190 and 0.156 hydroxylequivalent of polyethylene glycol) are combined with 57.2 grams (0.300epoxide equivalent) of Epoxide 190 and 48.4 grams (0.628 anhydrideequivalent) of hexahydrophthalic anhydride. The mixture is heated withstirring at 50 C. to C. until a clear .solution results. To the solutionis added with stirring, 0.25 gram of dimethylaminomethylphenol. Theresulting blend is cast between glass plates and is baked at 150 C. forthirty minutes in a circulating oven followed 8 bya two and one-halfhour bake at 180 C. The cast ing obtained has the following physicalproperties:

Tensile strength 1b./sq. in 9,300 Flexural strength lb./sq. in 15,600Elongation percent.. 4.5 Impact strength ft. lb./in. notch 0.43 Hardness(Rockwell M) 88 Water absorption percent 0.3

EXAMPLE 2 A. Copolymer preparation Material Units Weight Methyl Alcohol8. 0 4. Maleie Anhydride 24. 5 73. Methyl Aerylate 67. 5 202. BenzoylPeroxide 2.0 6. Polyethylene Glycol (Molecular Weight 300).; 200.

To prepare monomethyl maleate, in one liter, threenecked, round-bottomflask, the methyl alcohol and maleic anhydride are heated at C. for onehour. The flask contents are cooled to room temperature and the methylacrylate and benzoyl peroxide are combined with the monomethyl malea-teto make a monomer-catalyst mixture. These proportions represent (basedon the total weight of the reactants) 32.5 weight percent of monomethylmaleate and 67.5 weight percent of methyl acrylate. In another oneliter, three-necked, round-bottomed flask fitted with an agitator,thermometer, condenser and dropping funnel, the polyethylene glycol isheated to 125 C. at which time the addition of the monomer-catalystsolution is started by means of the dropping funnel at a fast drop rate.During the addition, two hours and twenty minutes, the reactiontemperature is maintained below the reflux temperature. When theaddition is complete, the reaction is held at C. to C. for an additionalhour after which it is cooled to room temperature. The flask 'is fittedfor vacuum distillation and any excess monomer is distilled off at 15mm. Hg and 120 C., in this case only a few drops. The

flask contents are cooled and the 60 percent carboxy copolymer solutionin polyethylene glycol is poured into a suitable container. Thecopolymer portion of the composition has a theoretical carboxyequivalent of 400, while the total copolymer solution has a carboxylequivalent of 667 and a hydroxyl equivalent of 240.

B. Cured composition In a suitable container, 64.0 grams of thecopolymer solution of this example (0.096 carboxyl equivalent ofcopolymer and 0.172 hydroxyl equivalent of the glycol) are combined with52.8 grams (0.684 anhydride equivalent) of hexahydrophthalic anhydrideand 83.2 grams (0.436 epoxide equivalent) of Epoxide 190. i The mixtureis heated with stirringat 80 C. to'100 C. until solution occurs. To thesolution is added with stirring 0.25 gram dimethylaminomethyl phenol.The mixture is cast between .glass plates, and is heated at 100 C. forone hour followed by a bake of two hours at C. The resulting clearcasting has these physical properties:

Tensile strength lbs./sq. in... 2000 Elongation percent 1150 Impactstrength ft. lb./ in. notch 0.55 Hardness (Shore D) 66 Water absorptionpercent 0.6

Another casting is prepared and cured as above from 64.8 grams of thecopolymer solution of this example (0.096 carboxyl .equivalent of thecopolymer and 0.172 hydroxyl equivalent of the glycol) combined with84.0 grams (0.440 epoxide equivalent) of Epoxide 190, 51.2 grams (0.692anhydride equivalent) of phthalic anhydride comma In a 500 ml.round-bottomed, three-necked flask equipped with an agitator,thermometer, reflux condenser and dropping funnel, the vinyl acetate,crotonic acid and benzoyl peroxide are heated to reflux (78 C. to 80C.). These proportions represent (based on the total weight of the tworeactants) 80.0 weight percent of vinyl acetate and 20.0 weight percentof crotonic acid. In an Erlenmeyer flask, the hexahydrophth-alicanhydride is dissolved by heating in polyethylene glycol (molecularweight=300) The monomer-catalyst mixture is held at reflux until thesolution becomes highly viscous (about three and onehalf hours) at whichtime the diluent mixture is added to the flask contents through thedropping funnel at a moderate dropwise rate over a period of about onehour. As the amount of diluent present increases, the reflux temperatureincreases, however, thereaction temperature is not allowed to exceed 135C. and when all of the diluent is added, the reaction mixture ismaintained at this temperature until reflux ceases. The 39.5 percentcarboxy copolymer solution in a 32.8 percent/67.2 percent mixture ofglycol and anhydride is allowed to cool to room temperature. Thecopolymer portion of the composition has a carboxyl equivalent of '430grams while the total copolymer solution has a carboxyl equivalent of1088, a hydroxyl equivalent of 756 and an anhydride equivalent of 189.

B. Cured composition With stirring 130.0 grams (0. 112 carboxylequivalent of copolymer, 0.156 hydroxyl equivalent of glycol and 0.632anhydride equivalent of anhydride) of the copolymer solution of thisexample and 80.0 grams (0.420 epoxide equivalent) of Epoxide 190 areheated at 80 C. to 100 C. until homogeneous solution results. mixture isblended, with stirring, 0.25 gram of dimethyla-minomethyl phenol. Themixture is cast between glass plates and is baked at 100 C. for one hourfollowed by a two hour bake at 150 C. The resulting clear castingexhibits the following physical properties:

Tensile strength lb./sq. in 2500 Elongation percent 90 Impact'strengthft. lb./in. notch 0.45 Hardness (Rockwell M) 30 Water absorption"percent" 0.6

Into the 1 Dimerized soya fatty acid is a commercial form of a dimeriepolymer consisting essentially of dilinoleic acid. The method used inits preparation is set forth in the Journal of American Oil ChemistsSociety, March 1957, PP. 9-65.

Into a one liter, round-bottomed, three-necked flask fitted with athermometer, agitator, dropping funnel and reflux condenser are chargedthe dimerized soya fatty acids. While in a separate container, amonomer-catalyst solution is prepared by combining the vinyl toluene,methyl acrylate, methacrylic acid and benzoyl peroxide. Theseproportions of monomers in the monomer-catalyst solution represent(based on the total weight of the three reactants) 60 weight percent ofvinyl toluene, 20 weight percent of methyl acrylate, and 20 weightpercent of methacrylic acid. The dimerized soya fatty acids are heatedto C. with agitation after which the monomer-catalyst solution is slowlyintroduced into the flask by means of the dropping funnel over a periodof about one and onehalf hours. During this addition, the reactiontemper-ature is held under C. After all of the monomercatalyst solutionis added, the reaction mixture is heated at slow reflux to a temperatureof C. over a period of an hour after which heating is discontinued andthe resulting 50 percent carboxy copolymer solution is poured into asuitable container. The copolymer portion of the composition has atheoretical weight per carboxyl group of 430 while the diluent has aWeight per carboxyl group of 306. The total copolymer solution has acarboxyl equivalent of 357.

B. Cured composition In a suitable container, 79.6 grams of the 50percent copolymer solution of this example (0.092 carboxyl equivalent ofcopolymer and 0.128 carboxyl equivalent of diluent) are combined with80.0 grams (0.420 epoxide equivalent) of Epoxide and 40.8 grams (0.528anhydride equivalent) of hexahydrophthalic anhydride and are heated to50 C. to 80 C. with agitation until solution occurs. Into this solutionis blended with stirring 0.25 gram of dimethylaminomethyl phenol. Themixture is cast between glass plates and is heated in a circulating ovenat 150 C. for thirty minutes followed by a In accordance with Example 1,the Epoxide 200 is heated to 125 C. The monomer-catalyst solution madeup of vinyl toluene, methyl acrylate, methacrylic acid and catalyst isthen added to the preheated epoxide diluent. During the addition of themonomer-catalyst solution, a period of one and one-half hours, thetemperature of the flask contents are held below 125 C. After theaddition is complete, the flask contents are held at 125 C. until refluxceases, producing a 50 percent solution of a 60/ 20/ 20' vinyltoluene/methyl acrylate/methacrylic acid polymer in Epoxide 200. Thecopolymer portion of the composition has a theoretical carboxylequivalent of 430 while the total copolymer solution has a theoreticalcarboxyl equivalent of 860.

The resulting product is a viscous solution which on further heatingforms a tough, flexible, insoluble, infusible product.

EXAMPLE 6 A. Copolymer preparation Material Units Weight (grams) VinylToluene 60.0 120. Methyl Acrylate 20. 40. Methacrylic Acid- 20. 0 40.Benzoyl Peroxide 2. 0 4. .Hexahydrophthalic Anhydride 200.

A monomer-catalyst solution is prepared by combining the vinyl toluene,methyl acrylate, methacrylic acid, and benz-oyl peroxide in a flask. Thehexahydrophthalic anhydride is then heated in a one liter flask to 125C. and the monomer-catalyst mixture is added to the contents of theflask through a dropping funnel at a fast dropwise rate over a period ofabout one hour. After all of'the monomer-catalyst solution is added, thereaction mixture is heated at slow reflux to a temperature of 150 C.forming a 50 percent carboxy copolymer solution. The copolymer portionof the composition has a theoretical carboxyl equivalent of 430 whilethe total copolymer solution has a theoretical carboxy equivalent of 860and anhydride equivalent of 154.

B. Cured composition As outlined in Part B of Example 1, 96 grams of thecopolymer solution (.223 carboxyl equivalent of copolymer and .624anhydride equivalent of hexahydrophthalic anhydride) are combined with80.8 grams (.425 epoxide equivalent) of Epoxide 190 and 23.6 grams (.157hydroxyl equivalent) of polyethylene glycol. The mixture is heated withstirring at 80 C. to 110 C. To the solution is added with stirring .25gram of dimethylaminomethyl phenol. The resulting blend is cast andbaked as described in Example 1, producing a hard, infusible, insolubleproduct.

EXAMPLE 7 A. Copolymer preparation Material Units Weight (grams) VinylToluene 60. 0 120. 0 Methyl Acrylate 20. 0 40. 0 Methacrylic Acid 20. 040. 0 Benzoyl Peroxide 2. O 4. 0 Tctrahydrophthalic Anhydride 100. 0Hcxachloroendomethylenetetrahydrophthalic (HET) Anhydride 100. 0

wise rate over a period of about one and one-half hours. When all of themonomer-catalyst solution has been added, the temperature of thereaction mixture is increased to 150 C. and maintained there for aperiod of 45 minutes. The resulting product is a 50 percent solution ofa 60/20/20 vinyl toluene/methyl acrylate/ methacrylic acid polymer in a70/30 tetrahydrophthalic/ HET anhydride mixture. The copolymer portionof the composition has a carboxyl equivalent of 430 while the totalcopolymer solution has a carboxyl equivalent of 860 and an anhydrideequivalent of 251.

B. Cured composition EXAMPLE 8 A. Copo'lymer preparation Material UnitsWeight Styrene 60. 0 120. 0 Methacrylic Acid 40. 0 80. 0 BenzoylPeroxide 2. 0 4. 0 Polypropylene Glycol (Molecular Weight'1,200) 200. 0

In the manner described in Example 1, the polypropylene glycol is heatedto'.125 C. in a one liter flask. At this temperature, themonomer-catalyst solution, prepared by mixing together the styrene,methacrylic acid, and benzoyl peroxide, is added to the preheated glycoldiluent by means of a dropping funnel at a fast dropwise rate, over aperiod of about one hour. After the addition is complete, the flaskcontents are held at 135 C. until reflux ceases, forming a viscous, 50percent solution of a 60/ 40 styrene/methacrylic acid copolymer inpolypropylene glycol. The copolymer portion of the composition, whichappears clear, has a theoretical carboxyl equivalent of 215 whilethetotal copolymer solution has a theoretical carboxyl equivalent of 430and hydroxyl equivalent of 1198.

B. Cured composition In accordance with Part B of Example 2, 99.6 grams(.464 carboxyl equivalent of copolymer and .835 hydroxyl equivalent ofpolypropylene glycol) of the copolymer solution, 75.6 grams (.398epoxide equivalent) of Epoxide 190, and-25.2 grams (.327 anhydrideequivalent) of hexahydrophthalic anhydride are heated with stirring atC. to C. Into the mixture is added, with stirring, .25 gramdimethylaminomethyl phenol. In the manner described in Part B of Example2, the mixture is cured by heating at 100 C. for one hour followed by aC. bake for two hours, producing a casting which is very hard and quitetough and flexible.

' EXAMPLE 9 A. Copolymer preparation Following the procedure of Example1, the polypropylene glycol is heated in a one liter flask to 125 C. Themonomer-catalyst solution, prepared by mixing together the vinyltoluene, methacrylic acid, and catalyst, is then introduced into theflask containing the preheated glycol diluent at a fast dropwise rate.After the addition of the monomer-catalyst solution, a period of aboutonehalf hour, the flask contents are held at 135 C. until reflux ceases.The resulting product is a 50 percent solution of a 60/40 vinyltoluene/methacrylic acid copolymer in polypropylene glycol. Thecopolymer portion of the composition has a theoretical carboxylequivalent of 215 while the total copolymer solution has .a theoreticalequivalent of 430 and hydroxyl equivalent of 750.

B. Cured composition EXAMPLE 10 A. Copolymer preparation Material UnitsWeight (grams) Vinyl Acetate 80. 120. 0 Crotonic Acid 20. 0 30. 0Benzoyl Peroxide 3. 0 4. Polypropylene Glycol (Molecular Weight 1,200)150v 0 In accordance with the preceding examples, the vinyl acetate,crotonic acid, and benzoyl peroxide are heated to reflux (75 C. to 77C.) in a 500 milliliter flask. When the viscosity of the flask contentsreaches the point where more agitation is needed, the polypropyleneglycol is added by means of a dropping funnel at a moderate dropwiserate. After the addition is complete, the reaction mixture is held atreflux (135 C.) for twenty minutes. The resulting product is a 50percent solution of a 80/20 vinyl acetate/crotonic acid copolymer inpolypropylene glycol. The copolymer portion of the composition has atheoretical carboxyl equivalent of 430 While the total copolymersolution has a theoretical carboxyl equivalent of 862 and hydroxylequivalent of 1200.

B. Cured composition EXAMPLE 11 A. Copolymer preparation Material UnitsWeight (grams) Vinyl Acetate 240. 0 Crotonic Acid"--. 60. 0 BenzoylPeroxide 12.0 Polypropylene Glycol (Molecular Weight 7 300. 0

According to the preceding examples, the vinyl acetate, crotonic acid,and benzoyl peroxide are heated in a one liter flask to reflux (78 C. to80 C.). To this monomer-catalyst solution is added 300 grams ofpolypropylene glycol in 50 gram increments, the frequency of theadditions depending on the viscosity of the solution. After the additionis complete, the flaskcontents are held at reflux until the refluxtemperature reaches 125 C. to 130 C. The resulting product is a 50percent solution of a 20 vinyl acetate-crotonic acid copolymer inpolypropylene glycol. The copolymer portion of the composition has atheoretical carboxyl equivalent of 430 while the total copolymersolution has a theoretical carboxyl equivalent of 860 and hydroxylequivalent of 750.

B. Cured composition A. Copolymer preparation Material Units WeightEpoxide 177 10 In accordance with Example 3, the vinyl acetate, crotonicacid, and benzoyl peroxide are heated in a 500 milliliter flask toreflux (78 C. to 80 C.). The monomer-catalyst mixture is held. at refluxuntil the solution becomes highly viscous (about one and one-half hours)at which time 50 grams of the diluent, diglyc'idyl ether of tn'methylol\propane, are added to the flask contents. After approximately thirtyminutes, another 50 grams of the diluent are added to the flaskcontents. The reaction mixture is held at reflux until the refluxtemperature reaches C. The resulting product is a 50 percent solution ofan 80/20 vinyl acetate/crotonic acid copolymer in Epoxide 177. Thecopolymer portion of the composition has a carboxyl equivalent of 430while the total copolymer solution has a carboxyl equivalent of 862 andepoxide equivalent of 354.

B. Cured composition EXAMPLE 13 A. Copolymer preparation Material UnitsWeight (grams) Vinyl Acetate 80. 0 80. 0 Crotonic Avid 20.0 20.0 BeuzoylPeroxide 4. 0 4.0 Epoxide 155. 100.0

In accordance with the preceding examples, the vinyl acetate, crotonicacid, and benzoyl peroxide are heated together in a 500 milliliter flaskto reflux (78 C. to 80 C.). After this monomer-catalyst solution hasrefluxed 15 for approximately one and one-half hours, the Epoxide 155 isadded to the solution. Reflux of the reaction mixture is continued untilthe temperature reaches 90 C. to 95 C. The resulting product is a 50percent solu- 16 I The'following table illustrates other compositions ofthe invention. In the table, the copolymer is identified as 60/20/20 VTMA/ MAA.. This is a terpolymer of '60 parts by weight vinyl toluene, 20parts by weight ti-on of a 80/20 vinyl acetate/crotonic acid copolymermethyl acrylate', and 20 parts methacrylic acid. Other 1n Epoxide 155.The copolyrner portion of the compodesignations are explained in thefootnotes to the table. sition has a theoretical carboxyl equivalent of430 while In the equivalent ratio portion of the table, the column thetotal copolymer solution has a carboxyl equivalent headed ReactiveDiluent includes only diluents such as ofv 862 and an epoxide equivalentof 300. acids or alcohols which are not in one of the other ratio B C dcolumns. If part or all of the diluent is an epoxide or We Compost ananhydride, that portion is included in the anhydride In the mannerdescribed in Part B of Example 1, 200 or epoxide column. PEG 300, 600,etc. as used in the grams (.465 carboxyl equivalent of copolymer and.666 table, represents a mixture of polyethylene glycols havepoxideequivalent of Epoxide 155) of the copolymer ing an average molecularweight of 300, 600, etc., as the solution is heated at 80 C. to 100 'C.To this solution case may be. All of the products whose properties areis added .1 gram of dimethylaminomethyl phenol with set forth in thefollowing table were cured for one hour stirring. As described in Part Bof Example 12, the reat 100 C. and'the'n post-cured for two hours at 150C. sulting mixture is cured to produce an infusible insoluble using onepercent dimethylaminomethyl phenol as a catresin which is very flexibleand quite soft. alyst.

TABLE I Copol- Copol- Equivalent Ratios ymer ymer No. Copolymer Concen-Car- Reactive Diluent Copolymer-Diluent v tration boxyl AppearanceCopol- Dil- Anhy- Epox- Percent Equivymer uent dride 1 ide alent 00 /20VT/MA/MAA 50 .430 PEG 300 sli g ht haze, non- 1.0 2.87 5.48 7.75

. OW. 00/20/20 VT/MA/MAA 50 430 PEG 000 Clear, I10n-fl0w 1.0 1.43 2. 883. 88 60/ 0/20 V /MA/ m 50 430 50% Epox. 190, 50% PEG 300- o--- 1.0 1.42 2. 85 3.80

60/20/20 VT/MA/MAA 50 430 50% 2 ET Hexauol, 50% PEG Clear, flow 1. 03.09 12. 4 13. 4

300. 60/20/20VT/MA/MAA 50 4 13-4 Slifighl haze, non- 1.0 I 2.21 17.7518.8

017V. 60/20/20 VT/MA/MAA 50 4'30 Dimer Acids Clear, non-flow- 1. 0 1.405 2. 84 4. 51 0 VT/MA/MAA 33% 430 50% 1 3 11 1 5 Acids, 50% Clear,flows 1. 0 1. 408 2.80 4.53 8 00 20 20 vT MA/MAA.-.'.--- 430 DimerAcids, 50% Injcizompatihle, non- 1.0 1.408 2.80 4.53

H ow. 9 60/20/20 VT/MA/MAA 50 430 31%]?020 Fatty Acids, 69% -d0. 1. 0 1.3 2. 87 3. 88

i P 0----- (50/20/20 33% 430 50% Dimer Acids, 50% Incompatible,flows. 1. 0 1. 07 2. 90 3. 78

HHPA. 11 60/20/20 STY/MA/MAA. 50 430 PEG 00 Slight haze, r1011- 1. 0.638 1. 050 2.

OW. 0 T 33% 430 50;; 7 Dimer Acids, 50% Hazy, flows 1. 0 1. 408 2. 80 4.53

EPA. 80/20 MA/MAA- 50 430 Clear, flows 1. O 1. 43 2. 87 3. 88 /40MA/MAA- 50 215 Clear, non-flows. 1. 0 .72 1. 44 2. 43 60/40 VT/MAA- 33%215 Inftiompatible, non- 1. 0 704 1. 395 2. 76

OW. 66% 00 Clear, flows 1. 0 3. 56 7. 15 8. 10 00% 800 0. 1.0 3.50 7.108.07 66% 300 Clear, non-fiow 1. 0 1. 178 3.95 4. 95 05% 800 d 1. 0 1. 155. 82 0. 79 50 400 1. 0 1. 77 3. 04 4. 02 00 400 1.0 1.78 3. 01 4.55 00450 1. 0 505 2. 94 3. 92 00 400 1. 0 583 1. 938 2. 93 50 400 33% PEG300, 07% HHPA- 1. 0 .605 2. 94 3. 92 8/ 2 MA/MBM- 42. 9 800 10% PEG300.84% HHPA 1. 0 1.10 5. 82 5. 79 78/22 MA/MBM 50 800 33% PEG 300, 57%1111121.-.- fl 1. 0 1. 178 3. 95 4. 95

. OW. 78/22 MA/MBM 00 00 33% PEG 300, 07% HHPA. do. 1. 0 1.1 5. 82 6. 793 A/MBM 50 400 33% PEG 300, 07% HHPA Clear, slight fl0w.. 1. 0 .875 4.38 5. 30 M M 50 400 33% PEG 300, 57% 1111124---- Clear, flows 1. 0 .8754.38 5. 30 71/29 MA/ 00 800 33% PEG 300, 07 HHPA 1. 0 1.178 3. 95 4. 9571 29 MA/MEHM- 00 800 33% PE G 300, 57 0 HHPAL- 1. 0 1.16 5. 82 5. 7943/57 MA/MEHM 50 400 33% P G 300, 57 o HEP/1" 1. 0 .595 2. 95 7. 57 4220 38 MA/VT/MEHM- 50 500 1. 0 1. 32 5. 50 7. 55 31/31/38 MA/VT/MEHM 50650 1. 0 1. 33 3.29 4. 28 31/31/38 MA/VT/MEHM. 50 000 1. 0 1.32 5. 55 7.55 31/31/38 MM/VT/MEHM- 50 000 1. 0 1. 32 0. 55 7. 50 20/42/38MA/VT/MEHM 50 500 1. 0 1. 32 5. 50 7. 55 09/31 MA/MD33M 00 000 1. 0 .832. 90 3. 92 59/31 MA/MD M. 50 500 1.0 .875 4.38 5.40 5 49 MA/MD4M 50 0001.0 1.32 3.25 4.20 80 20 VAe/CA 50 430 1. 0 2. 850 5. 75 5. 73 0/20 /0A05% 430 EG 300 1. 0 1. 45 2. 87 3. 80/20 /CA 39% 430 33% PEG 300, 07%HHPA 1. 0 1. 45 2. 80 3.81 80/20 VAc/ A 50 430 33% PEG 300, 07% HHPA 1.0 .945 1.859 2. 72 0 A 50 430 PEG 5 1. 0 1. 457 2. 90 3.88 80/20 VAC/CA50 430 1. 0 1. 43 2 2. 98 3.87 80/20 VAe/CA 33 4 1. 0 1. 148' 2. 73 3.84 80/20 VAc/CA 33% y 430 1.0 1.145 3.80 4.80 80/20 VAc/CA 33% 430 50%-1G 750, HHPA 1. 0 1.145 5. 75 0. 75

MD MMonoethylene glycol-p-tert-butylphenyl ether maleate.

l Hexahydrophthalic Anhydride unless otherwise specified. 2 PhthalicAnhydride.

VTVinyl Toluene.

MAMethyl Aerylate. MAA-Methacrylic Acid. STY-Styrene.

MMMMonomethyl Maleate. MBM-Monobutyl Maleate. MMMethyl Methacrylate.MEHM-Mono-Z-Ethyl Hexyl Maleate.

MD MMonomaleate ester of Propylene Glycol Methylether.

CA-Crotonic Acid.

VAc-Vinyl Acetate.

HHPib-Anhydride of Example 4.

D-4-Ethylene GlycoLp-tert-butylphenyl Ether, Mol. Wt. 194.3.

Dimer AcidsThose acids of Ex. 1. 0000 Fatty AcidsA mixture of fattyacids, 5 major portion of which is lauric acid, obtained by doubledistillation of coconut oil and available commercially.

TABLE I-Continued Tensile Flexure Percent No. Percent Impact Hardness 3Water Elongation (Notched) Absorption Ult. Md. 10 Ult. Mod. 10

4 900 7.0 55D 1. 3 9,300 21 43 88M .3 9, 800 24 46 95M 1 9,800 24 47102M 09 6, 900 18 26 81M 1 4 3,500 .09 25 55M l 2, 300 07 26 36M 1 3,400 06 112 1. 8 74D 1. 1 ,60 50 5, 200 17 22 80D 1 5, 300 19 2. 9 10,000 41 22 90M 1 4, 600 11 4 30 5, 900 19 27 56M 1 900 127 No Break (16#44D 2. 2

ARM) 3, 000 4 68 1. 1 7513 1. 3 6, 200 13 4 10 27 89M 1 4, 400 09 60 4580D 4 9,500 19 11 48 83D 4 3, 000 07 4 73 37 78D 4 8, 000 4 16 44 85 22, 000 12 4 150 4 55 66D 6 4 4, 500 110 48 76D .6 4,500 10 40 .29 81D .31, 400 114 4 55 67D 4 7, 400 15 5. 6 35 79M 2 4 6, 200 13 15 47 78M 22,800 .04 98 .48 71D .4 6, 900 14 4 17 34 84D 2 9, 600 25 5 42 89M 1 49, 300 15 5 4 .37 86]) 2 1, 700 4 120 24 72D .3

, 600 O9 4 24 19 60M 42 3, 300 4 50 4 45 78D 2 ,900 23 4. 2 .37 91M 1 2,300 05 92 .43 76D .3 8, 900 23 4 40 92M 1 9, 100 .23 3. s 33 95M 1 49,600 5 4 42 88M 1 2, 000 4 115 .49 69D .5 400 11 4 25 47 71M 2 1, 500 4185 33 66D 4 3, 100 05 125 42 79D 5 5, 300 14 4 50 44 841) 5 2, 500 05 490 4 45 M 6 4 2,900 11 41 .40 56M 6 500 110 No Break 38D 2. 5 1, 300 4225 No Break 53D 2.1

500 07 4 90 3. 0 85A 56 1, 550 12 4 90 4 1. 3 65D 3, 900 12 34 4 44 80D22 3 M-Rockwell M Scale; other letters refer to Shore.

4 Average of several duplicates.

The foregoing examples show that by the practice of this invention, itis not only possible to incorporate the copolymers into castingcompositions, but products containing up to 25 to 30 percent copolymerare prepared having physical properties comparable to many epoxysystems. It is understood that properties of castings will vary not onlywith the monomers and the carboxy equivalent of the copolymer, but withthe various cross-linking agents. Hence, a wide variation of operationand products is possible within the spiritot this invention. Suchvariations and modifications are deemed to be within the scope of thisinvention.

What is claimed is:

1. A process for the preparation of a cross-linked carboxy copolymerwhich comprises forming a solution of an uncrosslinked carboxy copolymerdevoid of solvent boiling below 150 C. by polymerizing, at a temperatureof from 60 C. to about 150 C., a solution comprising (A) anu,,8-ethy1enically unsaturated carboxylic acid containing not more thanfour carbon atoms,

(B) a different monoethylenically unsaturtaed monomer copolymerizablewith said (A), and

(C) as the sole polymerization solvent, a polyhydric alcohol,

said (C) (1) being a solvent for and non-reactive with said (A), said(B) and said uncrosslinked carboxy copolymer under the polymerizationconditions used.

(2) being present in an amount sufiicient to dissolve said (A), said (B)and said uncrosslinked carboxy copolymer,

(3) being saturated or containing unsaturation which is non-reactiveunder the polymerization conditions used,

(4) having a melting point below the polym erization temperature,

(5) having a boiling point of at least 150 C.,

(6) having a viscosity not exceeding centipoises at the polymerizationtemperature, and

(7) being capable of entering the curing reaction when saiduncrosslinked carboxy copolymer is cured, adding a polyepoxide and apolycarboxylic acid anhydride to said uncrosslinked carboxy copolymersolution to form a polycarboxylic acid anhydride: polyhydric alcohol:polyepoxide: uncrosslinked carboxy copolymer system having the ratio of2 equivalents of said polycarboxylic acid anhydride to 0.4-1.6equivalent of said polyhydric alcohol to 3 equivalents of saidpolyepoxide to 1 equivalent of said uncrosslinked carboxy copolymer, andheatcuring the resulting composition.

2. A process as described in claim l wherein said uncrosslinked carboxycopolymer solution is prepared by polymerizing (A) 20 percent ofmethacrylic acid,

(B) a mixture of 60 percent of vinyl toluene and 20 percent of methylacrylate, and

(C) a polyethylene glycol having an average molecular weight of about300, said polyepoxide is the diglycidyl ether of bisphenol A and saidpolycarboxylic acid anhydride is hexahydrophthalic anhydride.

- 3. A process as described in claim 1 wherein said (A) is methacrylicacid and said (B) is methyl acrylate.

3,247,287 19 I 4. A process as described in claim 1 wherein said (A) ismethacrylic acid and said (B) is vinyl toluene.

5. A process as described in claim 1 wherein said (A) is methacrylicacid and said (B) is a mixture of vinyl 8/1960 2,957,843 10/ 1960toluene and methyl acrylate. v v 2 965 602 12/1960 6. A process asdescribed in clalm 1 wherein said (C) 3:046:246 7/1962 is an etheralcohol.

7. A process as described in claim 1 wherein said (C) is a polyethyleneglycol.

8. A process as described in claim 1 wherein said (C) 10 is glycerol.

9. A process as described in claim 1 wherein said (C) istrimethylolpropane.

References Cited by the Examiner UNITED STATES PATENTS Belanger.

Anderson et al 26033.2 Hicks.

Muskat.

MORRIS LIEBMAN, Primary Examiner. J. W. BEHRINGER, K. B. CLARKE, A.LIBERMAN,

Assistant Examiners.

1. A PROCESS FOR THE PREPARATION OF A CROSS-LINKED CARBOXY COPOLYMERWHICH COMPRISES FORMING A SOLUTION OF AN UNCROSSLINKED CARBOXY COPOLYMERDVOID OF SOLVENT BOILING BELOW 150*C. BY POLYMERIZING, AT A TEMPERATUREOF FROM 60*C. TO ABOUT 150*C., A SOLUTION COMPRISING (A) ANA,B-ETHYLENICALLY UNSATURATED CARBOXYLIC ACID CONTAINING NOT MORE THANFOUR CARBON ATOMS, (B) A DIFFERENT MONOETHYLENICALLY UNSATURATED MONOMERCOPOLYMERIZABLE WITH SAID (A), AND (C) AS THE SOLE POLYMERIZATIONSOLVENT, A POLYHYDRIC ALCOHOL, SAID (C) (1) BEING A SOLVENT FOR ANDNON-REACTIVE WITH SAID (A), SAID (B) AND SAID UNCROSSLINED CARBOXYCOPOLYMER UNDER THE POLYMERIZATION CONDITIONS USED. (2) BEING PRESENT INAN AMOUNT SUFFICIENT TO DISSOLVE SAID (A), SAID (B) AND SAIDUNCROSSLINKED CARBOXY COPOLYMER, (3) BEING SATURATED OR CONTAININGUNSATURATION WHICH IS NON-REACTIVE UNDER THE POLYMERIZATION CONDITIONSUSED, (4) HAVING A MELTING POINT BELOW THE POLYMERIZATION TEMPERATURE,(5) HAVING A BOILING POINT OF AT LEAST 150*C., (6) HAVING A VISCOSITYNOT EXCEEDING 130 CENTIPOISES AT THE POLYMERIZATION TEMPERATURE, AND (7)BEING CAPABLE OF ENTERING THE CURING REACTION WHEN SAID UNCROSSLINKEDCARBOXY COPOLYMER IS CURED, ADDING A POLYEPOXIDE AND A POLYCARBOXYLICACID ANHYDRIDE TO SAID UNCROSSLINKED CARBOXY COPOLYMER SOLUTION TO FORMA POLYCARBOXYLIC ACID ANHYDRIDE: POLYHYDRIC ALCOHOL: POLYEPOXIDE:UNCROSSLINED CARBOXY COPOLYMER SYSTEM HAVING THE RATIO OF 2 EQUIVALENTSOF SAID POLYCARBOXYLIC ACID ANHYDRIDE TO 0.4-1.6 EQUIVALENT OF SAIDPOLYHYDRIC ALCOHOL TO 3 EQUIVALENTS OF SAID POLYEPOXIDE TO 1 EQUIVALENTOF SAID UNCROSSLINKED CARBOXY COPOLYMER, AND HEATCURING THE RESULTINGCOMPOSITION.